1996 ES 300 - Original owner -115,985 miles and runs great. I hosed down a cold engine with cold high pressure water hose to clean off engine compartment. A few days later the Amber "Check Engine" light illuminated while on the freeway. We don't have the "Trac Off" Light. What is that? There are no transmission issues. Everything runs great.
I hosed down a cold engine again with high pressure cold water. Reason. Make it fail so it can be found. Light stayed on, no transmission issues.
After a few days and about 50 miles the light went away. After about a week the light came back on again at engine start. Transmission and all work great. Smooth shifting and no sign of trouble. I Checked gas cap and it looks clean and appears to seal nicely.
I'm thinking I got water up into a switch or sensor somewhere. Maybe it will dry out and go away again.
I Will have dealer read the computer soon.